MoqException: All invocations on the mock must have a corresponding setup

Ensure:

• You've instantiated the mock

var myService = new Mock<IMyService>(Strict);

• You've called Setup on your instantiation, with arguments which match EXACTLY what will be called during test execution by the real code (all arguments should be specified, even if they're null/default)

myService
    .Setup(s => s.MyMethod(
        "somePreciseString",
        It.IsAny<Guid>(), // Any GUID
        It.IsAny<bool?>(), // Any nullable boolean
        true, // Specific boolean
        null)) // Optional parameter
    .Returns(Task.CompletedTask);

• Any implementing services include your instantiation

var myComplexService = BuildComplexService(
    myService.Object
    mySecondService.Object
    myThirdService.Object
);

• All method calls on the mock are verified

mock.VerifyAll();